Movable platforms for supporting word processors, CRT display units, and other equipment are well known as disclosed, for example, in U.S. Pat. Nos. 4,515,086, 3,919,949, 3,702,209, and 3,643,605. In general, such platforms are mounted on adjustable arms or on swivel bases and, if they are guided for movement over a work surface, guide tracks either project upwardly from that surface or are recessed into the surface. In either of the latter cases, removal of the platform leaves the work surface with obstructions or recesses that may interfere with effective use of that surface and, in any event, are unattractive and undesirable.
An important aspect of this invention therefore lies in providing an assembly including a movable tabletop platform which requires no attachments or alterations in the work surface of the tabletop and which may therefore be removed when not needed without leaving any obstructions, holes, grooves, or other disfigurements on or in that surface. Nevertheless, the platform assembly does include guide means for guiding movement of the platform in a rectilinear path across the rear portion of the work surface and for limiting the extent of such travel along that surface.
Briefly, the assembly includes a generally rectangular platform having a top wall and depending front, side, and rear flanges defining a shallow downwardly-facing cavity or recess. A plurality of rollers are mounted within that cavity with their rotational axes parallel with the side flanges of the platform and with their bottom surfaces projecting slightly beneath the lower limits of the front and side flanges. The rear flange of the platform is provided with a rigid extension that projects substantially below the lower limits of the rollers and extends along a plane perpendicular to the platform's top wall and normal to the rotational axes of the rollers. An elongated track, considerably longer than the width of the platform, is secured to the rear surface of a tabletop to define an elongated guide channel for receiving the rear flange extension of the platform and for guiding movement of the platform across the tabletop's work surface. The track includes stop elements at its ends for engaging the rear flange extension and limiting the extent of platform movement along the track.
The platform is relatively simple and inexpensive in construction but is rugged enough to support relatively heavy equipment upon a table surface. The rollers are carried by elongated channel members and those members are mounted within the cavity of the platform in such a way as to reinforce and rigidify the platform as a whole. The elongated cylindrical rollers make substantial contact with the surface on which the platform is supported, thereby distributing the load carried by the platform and insuring that movement of the platform may be easily effected even when the platform supports a relatively heavy piece of equipment.
Other features, objects, and advantages of the invention will become apparent from the specification and drawings.